This invention relates to the control of cooking of eggs, particularly by viscosity measurement techniques. The cooking of eggs is commonly controlled automatically by the regulation of cooking time. However, the relationship between cooking time and degree of cooking is complex and the quality of eggs cooked by known cookers is variable and dependent upon user skills. Correct cooking time is a function of the number of eggs being cooked simultaneously as well as egg size, initial egg temperature and initial water temperature if used. Known egg cookers compensate for only the first of these variables, but this invention compensates automatically for all of these variables more or less.